Flash optimized using oled display

ABSTRACT

An image processing system includes an image sensor, an OLED display, a profile selection processor configured to select an output profile from among a plurality of pre-stored output profiles based at least in part on a digital representation of a target scene captured by the image sensor, and an image driver configured to drive the OLED display to display an image based on the selected output profile during a capture of an image of the target scene with the image sensor.

FIELD OF THE INVENTION

The present invention relates to image capture devices that may be usedin conjunction with devices such as organic light emitting diodes andother devices, including the same.

BACKGROUND

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for a number of reasons. Many of the materialsused to make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include OLEDs, organicphototransistors, organic photovoltaic cells, and organicphotodetectors. For OLEDs, the organic materials may have performanceadvantages over conventional materials. For example, the wavelength atwhich an organic emissive layer emits light may generally be readilytuned with appropriate dopants.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting. Several OLED materials andconfigurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and5,707,745, which are incorporated herein by reference in their entirety.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Color may be measured using CIE coordinates, which are wellknown to the art.

One example of a green emissive molecule is tris(2-phenylpyridine)iridium, denoted Ir(ppy)₃, which has the following structure:

In this, and later figures herein, we depict the dative bond fromnitrogen to metal (here, Ir) as a straight line.

As used herein, the term “organic” includes polymeric materials as wellas small molecule organic materials that may be used to fabricateorganic opto-electronic devices. “Small molecule” refers to any organicmaterial that is not a polymer, and “small molecules” may actually bequite large. Small molecules may include repeat units in somecircumstances. For example, using a long chain alkyl group as asubstituent does not remove a molecule from the “small molecule” class.Small molecules may also be incorporated into polymers, for example as apendent group on a polymer backbone or as a part of the backbone. Smallmolecules may also serve as the core moiety of a dendrimer, whichconsists of a series of chemical shells built on the core moiety. Thecore moiety of a dendrimer may be a fluorescent or phosphorescent smallmolecule emitter. A dendrimer may be a “small molecule,” and it isbelieved that all dendrimers currently used in the field of OLEDs aresmall molecules.

As used herein, “top” means furthest away from the substrate, while“bottom” means closest to the substrate. Where a first layer isdescribed as “disposed over” a second layer, the first layer is disposedfurther away from substrate. There may be other layers between the firstand second layer, unless it is specified that the first layer is “incontact with” the second layer. For example, a cathode may be describedas “disposed over” an anode, even though there are various organiclayers in between.

As used herein, “solution processible” means capable of being dissolved,dispersed, or transported in and/or deposited from a liquid medium,either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed thatthe ligand directly contributes to the photoactive properties of anemissive material. A ligand may be referred to as “ancillary” when it isbelieved that the ligand does not contribute to the photoactiveproperties of an emissive material, although an ancillary ligand mayalter the properties of a photoactive ligand.

As used herein, and as would be generally understood by one skilled inthe art, a first “Highest Occupied Molecular Orbital” (HOMO) or “LowestUnoccupied Molecular Orbital” (LUMO) energy level is “greater than” or“higher than” a second HOMO or LUMO energy level if the first energylevel is closer to the vacuum energy level. Since ionization potentials(IP) are measured as a negative energy relative to a vacuum level, ahigher HOMO energy level corresponds to an IP having a smaller absolutevalue (an IP that is less negative). Similarly, a higher LUMO energylevel corresponds to an electron affinity (EA) having a smaller absolutevalue (an EA that is less negative). On a conventional energy leveldiagram, with the vacuum level at the top, the LUMO energy level of amaterial is higher than the HOMO energy level of the same material. A“higher” HOMO or LUMO energy level appears closer to the top of such adiagram than a “lower” HOMO or LUMO energy level.

As used herein, and as would be generally understood by one skilled inthe art, a first work function is “greater than” or “higher than” asecond work function if the first work function has a higher absolutevalue. Because work functions are generally measured as negative numbersrelative to vacuum level, this means that a “higher” work function ismore negative. On a conventional energy level diagram, with the vacuumlevel at the top, a “higher” work function is illustrated as furtheraway from the vacuum level in the downward direction. Thus, thedefinitions of HOMO and LUMO energy levels follow a different conventionthan work functions.

More details on OLEDs, and the definitions described above, can be foundin U.S. Pat. No. 7,279,704, which is incorporated herein by reference inits entirety.

SUMMARY OF THE INVENTION

According to an embodiment, a method of selectively generating imageenhancing light using an embedded OLED display, includes capturing, withan image sensor, a digital representation of a target scene upondetection of an image capture command for capture of the target scene,detecting one or more characteristics of the target scene from thedigital representation, selecting a pixel output profile from among aplurality of stored output profiles based at least in part on the one ormore characteristics, and driving the OLED display to generate a lightoutput according to the selected pixel output profile to illuminate thetarget scene during capture of an image of the target scene with theimage sensor.

The one or more characteristics can include one or more of: a distanceof a focal object in the target scene from the image sensor, a locationof the focal object in the target scene, ambient light intensity, andambient light color.

The pixel output profile can be selected based at least in part on acharacteristic of the image sensor.

The characteristic of the image sensor can be a level of lightsensitivity of the image sensor.

The method can further include storing a record of pixel output profileselections, wherein selecting the pixel output profile is based at leastin part on the stored record.

The pixel output profile can be selected based at least in part on anexpected lifespan of a set of subpixels.

The pixel output profile can be configured to achieve a target color oflight at a target illumination level.

The pixel output profile can include illuminating a first set ofsubpixels at a first intensity level and illuminating a second set ofsubpixels at a second intensity level.

The first set of subpixels can be yellow subpixels and the second set ofsubpixels can be blue subpixels.

According to an embodiment, an image processing system includes an imagesensor, an OLED display, a profile selection processor configured toselect an output profile from among a plurality of pre-stored outputprofiles based at least in part on a digital representation of a targetscene captured by the image sensor, and an image driver configured todrive the OLED display to display an image based on the selected outputprofile during a capture of an image of the target scene with the imagesensor.

The profile selection processor can be configured to select the outputprofile based at least in part on a characteristic of the image sensor.

The characteristic of the image sensor can be a level of lightsensitivity of the image sensor.

The profile selection processor can be configured to select the outputprofile based at least in part on one or more characteristics of thetarget scene from the digital representation.

The one or more characteristics can include one or more of: a distanceof a focal object in the target scene from the image sensor, a locationof the focal object in the target scene, ambient light intensity, andambient light color.

The output profile can be a single image that provides a target colorbased upon one or more intensity levels assigned to a plurality ofsubpixels.

The output profile can include a series of images that each provide atarget color based upon one or more intensity levels assigned to aplurality of subpixels.

The image processing system can further include an image processorconfigured to adjust an image that has been captured by the image sensorbased at least in part on the selected output profile displayed duringcapture of the image.

The image processing system can further include a memory deviceconfigured to store a record of output profile selections, and theprofile selection processor can further be configured to select thepixel output profile based at least in part on the stored record.

The profile selection processor can further be configured to select thepixel output profile based at least in part on an expected lifespan of aset of subpixels.

According to an embodiment, a method of generating a flash for imagecapture using an OLED display having a plurality of pixels includesselecting an output profile from among a plurality of output profiles,driving a first subpixel configuration in each of the plurality ofpixels according to the output profile to illuminate a target scene,capturing, with the image sensor, a first image of the target sceneilluminated by the first subpixel configuration, driving a secondsubpixel configuration in the set of pixels according to the outputprofile to illuminate the target scene, capturing, with the imagesensor, a second image illuminated by the second subpixel configuration,and combining the first image and the second image.

The output profile can be configured to achieve a combined white lightimage on the OLED display.

The output profile is configured to achieve a color on the OLED displaythat offsets a detection characteristic of the image sensor.

The output profile can designate the first subpixel configuration toenergize a first-type subpixel a first number of times and the secondsubpixel configuration to energize a second-type subpixel a secondnumber of times different from the first number.

The first-type subpixel can be a yellow subpixel and the second-typesubpixel can be a blue subpixel.

The method can further include capturing a pre-image of the target scenewith the image sensor, and selecting the output profile based at leastin part upon data from the captured pre-image.

The output profile can be selected based on a color dispersion ofexisting light conditions detected in the pre-image.

The output profile can be selected based on a level of illuminationdetected in the pre-image.

The output profile can be selected based on the pre-image to illuminatethe target scene at a level required for the image sensor to capture animage above a threshold quality level.

The method can further include driving a third subpixel configuration ofa third-type subpixel in each of the plurality of pixels according tothe output profile to illuminate a target scene, capturing, with theimage sensor, a third image illuminated by the third-type subpixel, andcombining the third image with the first image and the second image.

The first-type subpixel can be a red subpixel, the second-type pixel canbe a green subpixel, and the third-type subpixel can be a blue subpixel.

According to an embodiment, an image processing system includes an imagesensor, an OLED display, a profile selection processor configured toselect a first output profile from among a plurality of pre-storedoutput profiles, an image driver configured to drive the OLED display todisplay a plurality of flash images based on the selected outputprofile, wherein each of the plurality of flash images are respectivelydisplayed during a corresponding operation of capturing an image of thetarget scene with the image sensor, and an image processor configured tocombine the plurality of captured images into a single image.

The output profile can be configured to achieve a combined white lightimage on the OLED display.

The output profile can be configured to achieve a color on the OLEDdisplay that offsets a detection characteristic of the image sensor.

The output profile can provide flash images including a first subpixelconfiguration to energize a first-type subpixel a first number of timesand a second subpixel configuration to energize a second-type subpixel asecond number of times different from the first number.

The first-type subpixel can be a yellow subpixel and the second-typesubpixel can be a blue subpixel.

The system can further be configured to capture a pre-image of thetarget scene with the image sensor, and the profile selection processorcan further be configured to select the output profile based at least inpart upon data from the captured pre-image.

The profile selection processor can be configured to select the outputprofile based on a color dispersion of existing light conditionsdetected in the pre-image.

The profile selection processor can be configured to select the outputprofile based on a level of illumination detected in the pre-image.

The profile selection processor can be configured to select the outputprofile based on the pre-image to illuminate the target scene at a levelrequired for the image sensor to capture an image above a thresholdquality level.

The plurality of flash images can include a first image that energizesred subpixels, a second image that energizes green subpixels, and athird image that energizes blue subpixels.

According to an embodiment, a method of generating a flash for imagecapture using an OLED, includes initiating capture of a target scenewith an image sensor, driving a first-type subpixel in a set of pixelsduring a first frame of a display-implemented flash cycle to illuminatethe target scene, driving a second-type of subpixel in the set of pixelsduring a second frame of the display-implemented flash cycle toilluminate the target scene, and completing capture of the target scenewith the image sensor.

The first-type subpixel can be a yellow subpixel and the second-typesubpixel can be a blue subpixel.

The method can further comprise driving a third-type subpixel in the setof pixels during a third frame of the display-implemented flash cycle toilluminate the target scene prior to completing capture of the targetscene.

The first-type subpixel can be a red subpixel, the second-type pixel canbe a green subpixel, and the third-type subpixel can be a blue subpixel.

According to an embodiment, an image processing system, includes animage sensor, an OLED display, a profile selection processor configuredto select a first output profile from among a plurality of pre-storedoutput profiles, an image sensor driver configured to initiate captureof the target scene with the image sensor, and an image driverconfigured to drive the OLED display to sequentially display a pluralityof images based on the selected output profile when the image sensordriver initiates capture of the target scene with the image sensor,wherein the image sensor driver is configured to complete capture of thetarget scene with the image sensor when the image driver completesdriving the OLED display to display the plurality of images.

The plurality of images can include a first image that energizes redsubpixels, a second image that energizes green subpixels, and a thirdimage that energizes blue subpixels.

The system can further be configured to capture a pre-image of thetarget scene with the image sensor, and the profile selection processorcan further be configured to select the output profile based at least inpart upon data from the captured pre-image.

The profile selection processor can be configured to select the outputprofile based on a color dispersion of existing light conditionsdetected in the pre-image.

The profile selection processor can be configured to select the outputprofile based on a level of illumination detected in the pre-image.

The profile selection processor can be configured to select the outputprofile based on the pre-image to illuminate the target scene at a levelrequired for the image sensor to capture an image above a thresholdquality level.

According to an embodiment, a first device comprising a first organiclight emitting device is also provided. The first organic light emittingdevice can include an anode, a cathode, and an organic layer, disposedbetween the anode and the cathode. The first device can include an imagesensor, the first organic light emitting device in a display, a profileselection processor configured to select an output profile from among aplurality of pre-stored output profiles based at least in part on adigital representation of a target scene captured by the image sensor,and an image driver configured to drive the OLED display to display animage based on the selected output profile during a capture of an imageof the target scene with the image sensor. The first device can be aconsumer product, an organic light-emitting device, and/or a lightingpanel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an organic light emitting device.

FIG. 2 shows an inverted organic light emitting device that does nothave a separate electron transport layer.

FIG. 3 shows cell phone including an organic light emitting deviceaccording to a disclosed embodiment.

FIG. 4 shows a block diagram of a mobile device 400 according to anembodiment of the disclosed subject matter.

FIG. 5 is a flowchart 500 of a first display-implemented flash modeaccording to an embodiment of the disclosed subject matter.

FIG. 6 is a flow chart 600 of a second display-implemented flash modeaccording to an embodiment of the disclosed subject matter.

FIG. 7 is a flow chart 700 of a third display-implemented flash modeaccording to an embodiment of the disclosed subject matter.

DETAILED DESCRIPTION

Various aspects or features of this disclosure are described withreference to the drawings, wherein like reference numerals are used torefer to like elements throughout. In this specification, numerousdetails are set forth in order to provide a thorough understanding ofthis disclosure. It should be understood, however, that certain aspectsof disclosure may be practiced without these specific details, or withother methods, components, materials, etc. In other instances,well-known structures and devices are shown in block diagram form tofacilitate describing the subject disclosure.

A single pixel in an OLED display is made of several subpixels, forexample, red, green and blue. The luminance of an OLED display with allsubpixels energized is limited by the power supply of the device inwhich the display is disposed. This power limit restricts the amount oflight that can be generated by a conventional display, which leaves theconventional OLED display less than adequate for use as a flash. Inaddition, generally each of the subpixels has unique performancecharacteristics which may fluctuate with usage. Management of suchsubpixel usage and performance characteristics may be critical in orderto maintain overall sustained display quality and avoid unwanteddeterioration of the displayed images.

The disclosed embodiments provide a display-implemented flash configuredto precisely manage the color generation and energy level of eachindividual pixel of an OLED display. FIG. 3 shows a cell phone 300including an OLED display 310 and an image sensor 320 suitable for anembodiment of the disclosed subject matter. The display 310 includes anarray of pixels 330, each including several subpixels 340. When theimage sensor 320 is activated to capture an image, the OLED display 310can be configured to generate a light output according to a selectedpixel output profile in order to illuminate a target scene. The outputprofile can take into account several factors and function on a subpixel340 level. The disclosed embodiments provide many advantages, includingincreased efficiencies of usage and reducing unnecessary burn-in impactfrom continued use.

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices,” Nature, vol. 395, 151-154, 1998;(“Baldo-I”) and Baldo et al., “Very high-efficiency green organiclight-emitting devices based on electrophosphorescence,” Appl. Phys.Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), which are incorporatedby reference in their entireties. Phosphorescence is described in moredetail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporatedby reference.

FIG. 1 shows an organic light emitting device 100. The figures are notnecessarily drawn to scale. Device 100 may include a substrate 110, ananode 115, a hole injection layer 120, a hole transport layer 125, anelectron blocking layer 130, an emissive layer 135, a hole blockinglayer 140, an electron transport layer 145, an electron injection layer150, a protective layer 155, a cathode 160, and a barrier layer 170.Cathode 160 is a compound cathode having a first conductive layer 162and a second conductive layer 164. Device 100 may be fabricated bydepositing the layers described, in order. The properties and functionsof these various layers, as well as example materials, are described inmore detail in U.S. Pat. No. 7,279,704 at cols. 6-10, which areincorporated by reference.

More examples for each of these layers are available. For example, aflexible and transparent substrate-anode combination is disclosed inU.S. Pat. No. 5,844,363, which is incorporated by reference in itsentirety. An example of a p-doped hole transport layer is m-MTDATA dopedwith F₄-TCNQ at a molar ratio of 50:1, as disclosed in U.S. PatentApplication Publication No. 2003/0230980, which is incorporated byreference in its entirety. Examples of emissive and host materials aredisclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which isincorporated by reference in its entirety. An example of an n-dopedelectron transport layer is BPhen doped with Li at a molar ratio of 1:1,as disclosed in U.S. Patent Application Publication No. 2003/0230980,which is incorporated by reference in its entirety. U.S. Pat. Nos.5,703,436 and 5,707,745, which are incorporated by reference in theirentireties, disclose examples of cathodes including compound cathodeshaving a thin layer of metal such as Mg:Ag with an overlyingtransparent, electrically-conductive, sputter-deposited ITO layer. Thetheory and use of blocking layers is described in more detail in U.S.Pat. No. 6,097,147 and U.S. Patent Application Publication No.2003/0230980, which are incorporated by reference in their entireties.Examples of injection layers are provided in U.S. Patent ApplicationPublication No. 2004/0174116, which is incorporated by reference in itsentirety. A description of protective layers may be found in U.S. PatentApplication Publication No. 2004/0174116, which is incorporated byreference in its entirety.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210,a cathode 215, an emissive layer 220, a hole transport layer 225, and ananode 230. Device 200 may be fabricated by depositing the layersdescribed, in order. Because the most common OLED configuration has acathode disposed over the anode, and device 200 has cathode 215 disposedunder anode 230, device 200 may be referred to as an “inverted” OLED.Materials similar to those described with respect to device 100 may beused in the corresponding layers of device 200. FIG. 2 provides oneexample of how some layers may be omitted from the structure of device100.

The simple layered structure illustrated in FIGS. 1 and 2 is provided byway of non-limiting example, and it is understood that embodiments ofthe invention may be used in connection with a wide variety of otherstructures. The specific materials and structures described areexemplary in nature, and other materials and structures may be used.Functional OLEDs may be achieved by combining the various layersdescribed in different ways, or layers may be omitted entirely, based ondesign, performance, and cost factors. Other layers not specificallydescribed may also be included. Materials other than those specificallydescribed may be used. Although many of the examples provided hereindescribe various layers as comprising a single material, it isunderstood that combinations of materials, such as a mixture of host anddopant, or more generally a mixture, may be used. Also, the layers mayhave various sublayers. The names given to the various layers herein arenot intended to be strictly limiting. For example, in device 200, holetransport layer 225 transports holes and injects holes into emissivelayer 220, and may be described as a hole transport layer or a holeinjection layer. In one embodiment, an OLED may be described as havingan “organic layer” disposed between a cathode and an anode. This organiclayer may comprise a single layer, or may further comprise multiplelayers of different organic materials as described, for example, withrespect to FIGS. 1 and 2.

Structures and materials not specifically described may also be used,such as OLEDs comprised of polymeric materials (PLEDs) such as disclosedin U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated byreference in its entirety. By way of further example, OLEDs having asingle organic layer may be used. OLEDs may be stacked, for example asdescribed in U.S. Pat. No. 5,707,745 to Forrest et al, which isincorporated by reference in its entirety. The OLED structure maydeviate from the simple layered structure illustrated in FIGS. 1 and 2.For example, the substrate may include an angled reflective surface toimprove out-coupling, such as a mesa structure as described in U.S. Pat.No. 6,091,195 to Forrest et al., and/or a pit structure as described inU.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated byreference in their entireties.

Unless otherwise specified, any of the layers of the various embodimentsmay be deposited by any suitable method. For the organic layers,preferred methods include thermal evaporation, ink-jet, such asdescribed in U.S. Pat. Nos. 6,013,982 and 6,087,196, which areincorporated by reference in their entireties, organic vapor phasedeposition (OVPD), such as described in U.S. Pat. No. 6,337,102 toForrest et al., which is incorporated by reference in its entirety, anddeposition by organic vapor jet printing (OVJP), such as described inU.S. Pat. No. 7,431,968, which is incorporated by reference in itsentirety. Other suitable deposition methods include spin coating andother solution based processes. Solution based processes are preferablycarried out in nitrogen or an inert atmosphere. For the other layers,preferred methods include thermal evaporation. Preferred patterningmethods include deposition through a mask, cold welding such asdescribed in U.S. Pat. Nos. 6,294,398 and 6,468,819, which areincorporated by reference in their entireties, and patterning associatedwith some of the deposition methods such as ink-jet and OVJD. Othermethods may also be used. The materials to be deposited may be modifiedto make them compatible with a particular deposition method. Forexample, substituents such as alkyl and aryl groups, branched orunbranched, and preferably containing at least 3 carbons, may be used insmall molecules to enhance their ability to undergo solution processing.Substituents having 20 carbons or more may be used, and 3-20 carbons isa preferred range. Materials with asymmetric structures may have bettersolution processability than those having symmetric structures, becauseasymmetric materials may have a lower tendency to recrystallize.Dendrimer substituents may be used to enhance the ability of smallmolecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the presentinvention may further optionally comprise a barrier layer. One purposeof the barrier layer is to protect the electrodes and organic layersfrom damaging exposure to harmful species in the environment includingmoisture, vapor and/or gases, etc. The barrier layer may be depositedover, under or next to a substrate, an electrode, or over any otherparts of a device including an edge. The barrier layer may comprise asingle layer, or multiple layers. The barrier layer may be formed byvarious known chemical vapor deposition techniques and may includecompositions having a single phase as well as compositions havingmultiple phases. Any suitable material or combination of materials maybe used for the barrier layer. The barrier layer may incorporate aninorganic or an organic compound or both. The preferred barrier layercomprises a mixture of a polymeric material and a non-polymeric materialas described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos.PCT/US2007/023098 and PCT/US2009/042829, which are herein incorporatedby reference in their entireties. To be considered a “mixture”, theaforesaid polymeric and non-polymeric materials comprising the barrierlayer should be deposited under the same reaction conditions and/or atthe same time. The weight ratio of polymeric to non-polymeric materialmay be in the range of 95:5 to 5:95. The polymeric material and thenon-polymeric material may be created from the same precursor material.In one example, the mixture of a polymeric material and a non-polymericmaterial consists essentially of polymeric silicon and inorganicsilicon.

Devices fabricated in accordance with embodiments of the invention canbe incorporated into a wide variety of electronic component modules (orunits) that can be incorporated into a variety of electronic products orintermediate components. Examples of such electronic products orintermediate components include display screens, lighting devices suchas discrete light source devices or lighting panels, etc. that can beutilized by the end-user product manufacturers. Such electroniccomponent modules can optionally include the driving electronics and/orpower source(s). Devices fabricated in accordance with embodiments ofthe invention can be incorporated into a wide variety of consumerproducts that have one or more of the electronic component modules (orunits) incorporated therein. Such consumer products would include anykind of products that include one or more light source(s) and/or one ormore of some type of visual displays. Some examples of such consumerproducts include flat panel displays, computer monitors, medicalmonitors, televisions, billboards, lights for interior or exteriorillumination and/or signaling, heads-up displays, fully or partiallytransparent displays, flexible displays, laser printers, telephones,cell phones, tablets, phablets, personal digital assistants (PDAs),laptop computers, digital cameras, camcorders, viewfinders,micro-displays, 3-D displays, vehicles, a large area wall, theater orstadium screen, or a sign. Various control mechanisms may be used tocontrol devices fabricated in accordance with the present invention,including passive matrix and active matrix. Many of the devices areintended for use in a temperature range comfortable to humans, such as18 C to 30 C, and more preferably at room temperature (20-25 C), butcould be used outside this temperature range, for example, from −40 C to+80 C.

Many mobile devices such as cell phones and tablets include front-facingcameras which may be used by a user of the camera to take a picture ofhimself/herself. To accommodate this common utilization, many deviceshave been designed with a front facing flash in addition to the standardrear flash to improve the picture quality of the images which are takenwhile the individual(s) are facing the phone's display. Such picturesare frequently taken in a low light condition. Using the phone's displayas a light source to generate a “flash” can save cost by reducing theneed for a separate flash for front facing pictures. For example, if thedisplay is a light emitting diode (LED) lit liquid crystal display(LCD), then the phone may be designed to energize the backlight at fullbrightness for a short period and synchronize the light pulse with theimage sensor, so the display-based flash is on while the image sensor isbeing read.

In theory the same technique could be implemented if the display is anorganic light emitting devices (OLED) and not an LCD. However, the powerconsumption of an OLED display depends on image content (unlike an LCD),and the power available for the display is limited by the power supply,so as to contain its size and heat generation. Techniques and devicesdisclosed herein provide ways to overcome the potential brightnesslimitation on the OLED display for use as a flash for an image capturedevice in which the OLED display is installed. The disclosed OLEDdisplay-implemented flash can produce image specific light of a colorgenerated by selectively energizing one or more subpixels in everypixel, or a subset of pixels, at predetermined levels as opposed toenergizing all subpixels simultaneously. By lowering or eliminating theenergy that would be spent on energizing an entire set of subpixels, theremaining subpixels can be energized to higher levels and therebyachieve greater brightness.

The subpixel energization configurations in the discloseddisplay-implemented flash may be determined based on one or more factorsrelated to the environment, desired image effects, or the image sensorthat will be used to capture the image. Example environmental factorsinclude characteristics of a target scene to be captured, such a lightlevel and the color of ambient light. Image sensor factors includeoptomechanical characteristics of an image sensor that will be used tocapture the target scene. Image effects factors include specific effectsto be achieved based on default or user settings.

The subpixel configuration can be determined at the time of capture, forexample, triggered by an image capture command. Upon detecting an imagecapture command such as activation of a camera button, a remote picturecommand or other user interface element that activates a camera on thedevice, the image capture device can either calculate appropriate valuesfor each subpixel to generate a desired visual effect or select anoutput profile from among a stored set of output profiles.

Herein, a pixel output profile, or output profile, refers to one or morespecific configurations of subpixels and their respective energizationlevels for producing a particular luminous output on an OLED display. Anoutput profile can be configured to achieve a target color of light at atarget illumination level for a captured image by generating one or moreflash images on the OLED display. For example, one output profile may beconfigured to achieve an overall effect of a bright tint of red flashwhile another may be configured to achieve an overall effect of a softwhite light flash.

Output profiles can be configured to achieve target colors byilluminating designated subpixels at predetermined levels. For example,an output profile can be configured to illuminate a first set ofsubpixels (blue) at a first intensity level and illuminate a second setof subpixels (red) and a third set of subpixels (green) at an intensitylevel lower than the blue subpixels, thereby producing an overall effectof a blue-tinted white light flash.

Based on an output profile, subpixels can be illuminated at maximumbrightness without being constrained by power available from the displaypower supply when less than all of the display subpixels are energizedat the same time. In an example shown in FIG. 3, as the display 310 isaddressed at the display frame rate (e.g., 60 Hz), the discloseddisplay-implemented flash generates one flash color on the display forthe period of one frame.

As shown in timing diagram 350, in a first frame a blue subpixel “B” isenergized at 90% intensity to flash blue light. This is repeated withanother color for a subsequent frame, and then repeated for as manyframes in the flash cycle as required by the output profile. Incombination the flashes produce a designated color. In timing diagram350, blue “B”, red “R”, and green “G” subpixels are sequentiallyenergized at 90% intensity to produce white light in combination. Intiming diagram 360, blue “B” subpixels are energized at 50% intensityfor two frames followed by a red “R” subpixels energized at 90%intensity. Ideally, the subpixel selections and energization levels willbe configured to minimize lifetime impacts on the system. For example,in an OLED display in which the quality of light generated by bluesubpixels degrades at a faster rate than its red and green counterparts,the usage of blue subpixels should be utilized less than itscounterparts to maximize display performance over an extended period oftime.

Furthermore, output profiles need not be limited to sequentiallyenergizing one type of subpixel at a time. For example, an outputprofile could be configured to energize yellow subpixels at 90%intensity and blue subpixels at 10% intensity during a single frame. Asdisclosed in further detail herein, in some embodiments one or moresubpixel types may be illuminated at different points, such as withinthe same or different frames, and/or some subpixel types may not beilluminated.

In a mobile device (e.g., cell phone, tablet, laptop, etc.), the frontcamera of the device is generally used for self-portraits or otherbasically static images. In these situations a very fast exposure timefor the image sensor may not be required. Taking this into account, asensor read-out in the disclosed embodiments can be synchronized withthe display-implemented flash in at least three different flash modes,as will be described below.

FIG. 4 shows a block diagram of an illustrative mobile device 400according to an embodiment of the disclosed subject matter. The mobiledevice 400 includes an OLED display 410, an image sensor 420, a profileselection processor 430, a memory 440, and an image driver 450.

When the image sensor 420 receives a command to capture an image with anaccompanying display-implemented flash, the processor 430 eithercalculates a subpixel configuration profile for a flash image to begenerated by the display 410 based on a pre-image collected by the imagesensor 420 or selects an output profile from memory 440. The processor430 can select an output profile based on, for example, a defaultsetting, a user setting an automatic setting, one or morecharacteristics of a target scene, or/and one or more characteristics ofthe image sensor 420.

A single output profile or multiple output profiles may can be stored onthe memory 440. Memory 440 can be implemented as, for example, aninternal memory device of the mobile device 400 or an external memorydevice such as a card or network/cloud-based storage device.

If a single output profile is stored in memory 440, then the mobiledevice 400 will use that same individual output profile each time animage capture operation is executed. However, memory 440 can also storemultiple output profiles and a record of output profile selections. Therecord may be included as a determination factor for the processor'sselection of subsequent output profiles. For example, the processor 430may be configured to select output profiles in a pattern that alternateswhich subpixels are used to generate flash images so as to not overuse aparticular type or category of subpixel, e.g., subpixels of a particularcolor, operating status, or efficiency rating. The processor 430 mayfurther be configured to select an output profile based on an expectedlifespan of a set of subpixels in view of the record in order to extendthe overall lifespan of the OLED display 410. For example, afterblue-type subpixels have been used more than a threshold number of timesto generate flash images the processor may thereafter select outputprofiles that use blue-type subpixels with a lower frequency. This maybe useful, for example, to extend the lifetime of blue-type subpixels,which often have lower lifetimes and/or efficiencies than subpixels ofother types.

FIG. 5 is a flowchart 500 of an illustrative first display-implementedflash mode according to an embodiment of the disclosed subject matter.

Referring to FIGS. 4 and 5, in an example first flash mode as disclosedherein, at operation 510 the image sensor 420 captures a digitalrepresentation of a target scene. This initial representation, orpre-image, can be a full image capture or a type of partial scandesigned to test light conditions. In either case, the pre-imagecaptures information about the target scene. Based on the pre-image, atoperation 520 the processor detects one or more characteristics aboutthe target scene, for example, an estimated distance of a focal objectin the target scene from the image sensor 420, an estimate ambient lightintensity in the target scene, and/or an estimate ambient light color inthe target scene.

The processor can also be configured to detect characteristics of theimage sensor 420 itself, such as a level of light sensitivity of theimage sensor 420, a level of sensitivity of one or more specific colors,or an operational status of the image sensor. The processor 430 canfurther be configured to select an output profile, based on thepre-image, to illuminate the target scene at a level required for theimage sensor to capture an image above a threshold quality level.

For example, the processor 430 can select an output profile to generateenhancement light that has higher intensity peaks on red spectrum andlower intensity on lower spectrum subpixels, and then performpost-capture image correction taking the output profile into account andgenerate an output image with the desired color and illumination leveloutputs. In another example, the processor 430 can select an outputprofile to enhance light from one of a predetermined image class basedon the pre-image, for example, a profile to fill a soft flash for facialimages identified in the pre-image. In still another example, theprocessor 430 can select an output profile that includes apre-determined sequence of flash images, for example, a first flashimage that is an enhanced light that corrects for red eye and a secondflash image that corrects for lighting deficiencies. Again, theprocessor 430 may execute post-capture processing that takes the outputprofile into account but also uses red eye enhancer algorithms tofurther enhance the captured image.

At operation 530 the processor may select an output profile from memory440 based on the detected pre-image characteristics and/or image sensor420 characteristics. For example, when a target scene is detected tohave a high level of red ambient light, an output profile that includesa low level of red light may be selected. In another example, when theimage sensor 420 itself is determined to be highly sensitive to bluelight, an output profile that includes a low level of blue light may beselected.

At operation 540 the image driver 450 drives the OLED display 410 togenerate light output according to the selected pixel output profile andilluminate the target scene. While the target scene is illuminated, theimage sensor 420 captures an image of the target scene at operation 550.

FIG. 6 is a flow chart 600 of another example of a display-implementedflash mode according to an embodiment of the disclosed subject matter.

Referring to FIGS. 4 and 6, at operation 610 the processor selects anoutput profile from memory 440. At operation 620, in a first frame of adisplay-implemented flash cycle the image driver 450 drives the OLEDdisplay 410 to energize a first subpixel configuration according to theoutput profile. This illuminates the target scene with a first flashimage. For example, the first subpixel configuration could be a singletype of sub-pixel (e.g., all blue subpixels) or a combination of two ormore subpixels at predetermined levels (e.g., blue subpixels at 90% andgreen subpixels at 10%) to attempt to produce a specific wavelength oflight at a specific intensity. At operation 630 the image sensorcaptures a first image of the target scene illuminated by the firstsubpixel configuration flash image.

At operation 640 the image driver 450 enters the next frame of thedisplay-implemented flash cycle and drives the OLED display 410 toenergize another subpixel configuration according to the output profile.At operation 650 the image sensor captures another image of the targetscene as illuminated by the second subpixel configuration.

At operation 660 the processor determines whether any additional framesof the display-implemented flash cycle are necessary to completeexecution of the output profile. If additional frames are required,operations 640-650 are repeated until all flash images designated by theoutput profile have been executed. For example, the output profile maydesignate flashing a first configuration (e.g., blue subpixels at 90%)two times followed by flashing a second configuration (e.g., yellowsubpixels at 50%) one time. After all of the flash images designated bythe output profile have been executed and the corresponding target sceneimages have been captured by the image sensor 420, the processor 430combines the captured images at operation 670 to complete the capture ofthe image.

FIG. 7 is a flow chart 700 of another example display-implemented flashmode according to an embodiment of the disclosed subject matter.

Referring to FIGS. 4 and 7, at operation 710 the processor selects anoutput profile from memory 440. At operation 720 the image sensor 420initiates capture of an image of the target scene. Initiating capture ofan image may include, for example, processing pre-capture sensorsettings, executing an autofocus function and opening a shutter of theimage sensor 420.

At operation 730, during a first frame of the display-implemented flashcycle the image driver 450 drives the OLED display 410 to energize afirst subpixel configuration in each of the display 410 pixels,according to the output profile. For example, the image driver 450 mayenergize a first-type of subpixel in a set of pixels (e.g., bluesubpixels) to illuminate the target scene with a flash image. Atoperation 740 the image driver 450 drives the OLED display 410 toenergize another subpixel configuration in each of the display 410pixels according to the output profile. For example, the image driver450 may energize a second-type of subpixel in a set of pixels (e.g., redsubpixels) to illuminate the target scene with another flash image.

At operation 750 the processor determines whether any additional framesof the display-implemented flash cycle are necessary to completeexecution of the output profile. If additional frames are required,operations 730-740 are repeated until all flash images have beenexecuted. For example, referring to FIG. 3, an output profile can beconfigured to require a flash image of blue subpixels in a first frame,red subpixels in a second frame, and green subpixels in a third frame.

Referring back to FIG. 7, after all of the flash images designated bythe output profile have been executed the image sensor 420 completescapture of the image at operation 760. For example, completion of theimage capture may include closing the shutter and post-captureprocessing of the captured data. In this mode, through extended exposurethe image sensor innately combines the plurality of images capturedcorresponding to the flash images generated based on the output profile.

It should be understood that the above-described display-implementedflash modes are examples; many variations and combinations of theelements of the disclosed flash modes are possible. For example, thedisplay-implemented flash mode described in FIG. 6 may include theoperations of capturing a digital representation of a target scene anddetecting scene/sensor characteristics in order to select an outputprofile as described in operations 510 and 520 of FIG. 5.

Furthermore, the aforementioned mobile device systems have beendescribed in terms of interactions between components/blocks. A personof ordinary skill in the art would appreciate that such mobile devicesystems and components/blocks can include those components or specifiedsub-components, some of the specified components or sub-components,and/or additional components, according to various permutations andcombinations of the foregoing. Sub-components can also be implemented ascomponents communicatively coupled to other components rather thanincluded within parent components (hierarchical). Additionally, itshould be noted that one or more components may be combined into asingle component providing aggregate functionality or divided intoseveral separate sub-components, and any one or more middle layers, suchas a management layer, may be provided to communicatively couple to suchsub-components in order to provide integrated functionality. Anycomponents described herein may also interact with one or more othercomponents not specifically described herein but known by those ofordinary skill in the art. For example, the mobile device can include animage processor configured to adjust an image that has been captured bythe image sensor based at least in part on the selected output profiledisplayed during capture of the image.

Generally, in the disclosed embodiments an OLED display output profilecan be selected based on characteristics of the target scene and/orcamera sensor sensitivity. In an output profile, intensity, and ifnecessary, a number of frames of each flash image in a cycle can beadjusted to produce an optimum captured image of a target scene. Forexample, if a given sensor is not sensitive to a specific color, anoutput profile of the disclosed display-implemented flash can increasethe brightness of that color, or flash the color for multiple frames.Conversely, if the sensor is very sensitive to a specific color flash,an output profile can decrease its luminance, thereby improving capturedimage quality and preserving OLED lifetime.

The disclosed OLED display can be energized to produce multiple flashesfor each picture to be captured. For instance the display can producethree flashes of red, green and blue, each for a respective frame, suchthat the processor would integrate the three colors to result in whitelight. However, the disclosed embodiments are not limited thereto; theOLED display can flash other color combinations, for example, twoflashes of yellow (energizing red and green subpixels) and blue lightbased on an output profile. Furthermore, the display can flash two ormore blue flashes (two or more frame times of blue light) for each phototo be recorded, so as to reduce the peak display luminance (e.g., ofblue subpixels) to enhance display lifetime.

In a simplified implementation of the described invention in which theimage capture sensor is not providing an active feedback mechanism forselecting specific desired outputs from the OLED display acting as aflash, the system can select one of a small subset of preset flashoutputs which maximize the subpixel lifetimes without the need for imagepreprocessing. The specific flash may depend on user feedback or asimple low-light detection feedback mechanism, such as a low lightcondition, or take a no-color, gray-scale picture in which case one of asmall subset of subpixel illumination options will be used to drive theOLED display subpixels. In this case the digital representation of thetarget scene can be assumed to be one stored in the system withoutfurther processing by the image sensor.

It is understood that the various embodiments described herein are byway of example only, and are not intended to limit the scope of theinvention. For example, many of the materials and structures describedherein may be substituted with other materials and structures withoutdeviating from the spirit of the invention. The present invention asclaimed may therefore include variations from the particular examplesand preferred embodiments described herein, as will be apparent to oneof skill in the art. It is understood that various theories as to whythe invention works are not intended to be limiting.

1-19. (canceled)
 20. A method of generating a flash for image captureusing an OLED display having a plurality of pixels, comprising:selecting an output profile from among a plurality of output profiles;driving a first subpixel configuration in each of the plurality ofpixels according to the output profile to illuminate a target scene;capturing, with the image sensor, a first image of the target sceneilluminated by the first subpixel configuration; driving a secondsubpixel configuration in the set of pixels according to the outputprofile to illuminate the target scene; capturing, with the imagesensor, a second image illuminated by the second subpixel configuration;and combining the first image and the second image.
 21. The method ofclaim 20, wherein the output profile is configured to achieve a combinedwhite light image on the OLED display.
 22. The method of claim 20,wherein the output profile is configured to achieve a color on the OLEDdisplay that offsets a detection characteristic of the image sensor. 23.The method of claim 20, wherein the output profile designates the firstsubpixel configuration to energize a first-type subpixel a first numberof times and the second subpixel configuration to energize a second-typesubpixel a second number of times different from the first number. 24.The method of claim 23, wherein the first-type subpixel is a yellowsubpixel and the second-type subpixel is a blue subpixel.
 25. The methodof claim 20, further comprising: capturing a pre-image of the targetscene with the image sensor; and selecting the output profile based atleast in part upon data from the captured pre-image.
 26. The method ofclaim 25, wherein the output profile is selected based on a colordispersion of existing light conditions detected in the pre-image. 27.The method of claim 25, wherein the output profile is selected based ona level of illumination detected in the pre-image.
 28. The method ofclaim 25, wherein the output profile is selected based on the pre-imageto illuminate the target scene at a level required for the image sensorto capture an image above a threshold quality level.
 29. The method ofclaim 20, further comprising: driving a third subpixel configuration ofa third-type subpixel in each of the plurality of pixels according tothe output profile to illuminate a target scene; capturing, with theimage sensor, a third image illuminated by the third-type subpixel; andcombining the third image with the first image and the second image. 30.The method of claim 29, wherein the first-type subpixel is a redsubpixel, the second-type pixel is a green subpixel, and the third-typesubpixel is a blue subpixel.
 31. An image processing system, comprising:an image sensor; an OLED display; a profile selection processorconfigured to select a first output profile from among a plurality ofpre-stored output profiles; an image driver configured to drive the OLEDdisplay to display a plurality of flash images based on the selectedoutput profile, wherein each of the plurality of flash images arerespectively displayed during a corresponding operation of capturing animage of the target scene with the image sensor; and an image processorconfigured to combine the plurality of captured images into a singleimage.
 32. The image processing system of claim 31, wherein the outputprofile is configured to achieve a combined white light image on theOLED display.
 33. The image processing system of claim 31, wherein theoutput profile is configured to achieve a color on the OLED display thatoffsets a detection characteristic of the image sensor.
 34. The imageprocessing system of claim 31, wherein the output profile provides flashimages including a first subpixel configuration to energize a first-typesubpixel a first number of times and a second subpixel configuration toenergize a second-type subpixel a second number of times different fromthe first number.
 35. The image processing system of claim 34, whereinthe first-type subpixel is a yellow subpixel and the second-typesubpixel is a blue subpixel.
 36. The image processing system of claim31, wherein the system is further configured to capture a pre-image ofthe target scene with the image sensor, and wherein the profileselection processor is further configured to select the output profilebased at least in part upon data from the captured pre-image.
 37. Theimage processing system of claim 36, wherein the profile selectionprocessor is configured to select the output profile is based on a colordispersion of existing light conditions detected in the pre-image. 38.The image processing system of claim 36, wherein the profile selectionprocessor is configured to select the output profile based on a level ofillumination detected in the pre-image.
 39. The image processing systemof claim 36, wherein the profile selection processor is configured toselect the output profile based on the pre-image to illuminate thetarget scene at a level required for the image sensor to capture animage above a threshold quality level.
 40. The image processing systemof claim 31, wherein the plurality of flash images include a first imagethat energizes red subpixels, a second image that energizes greensubpixels, and a third image that energizes blue subpixels.
 41. A methodof generating a flash for image capture using an OLED, comprising:initiating capture of a target scene with an image sensor; driving afirst-type subpixel in a set of pixels during a first frame of adisplay-implemented flash cycle to illuminate the target scene; drivinga second-type of subpixel in the set of pixels during a second frame ofthe display-implemented flash cycle to illuminate the target scene; andcompleting capture of the target scene with the image sensor.
 42. Themethod of claim 41, wherein the first-type subpixel is a yellow subpixeland the second-type subpixel is a blue subpixel.
 43. The method of claim41, further comprising: driving a third-type subpixel in the set ofpixels during a third frame of the display-implemented flash cycle toilluminate the target scene prior to completing capture of the targetscene.
 44. The method of claim 41, wherein the first-type subpixel is ared subpixel, the second-type pixel is a green subpixel, and thethird-type subpixel is a blue subpixel.
 45. An image processing system,comprising: an image sensor; an OLED display; a profile selectionprocessor configured to select a first output profile from among aplurality of pre-stored output profiles; an image sensor driverconfigured to initiate capture of the target scene with the imagesensor; and an image driver configured to drive the OLED display tosequentially display a plurality of images based on the selected outputprofile when the image sensor driver initiates capture of the targetscene with the image sensor, wherein the image sensor driver isconfigured to complete capture of the target scene with the image sensorwhen the image driver completes driving the OLED display to display theplurality of images.
 46. The image processing system of claim 45,wherein the plurality of images include a first image that energizes redsubpixels, a second image that energizes green subpixels, and a thirdimage that energizes blue subpixels.
 47. The image processing system ofclaim 45, wherein the system is further configured to capture apre-image of the target scene with the image sensor, and wherein theprofile selection processor is further configured to select the outputprofile based at least in part upon data from the captured pre-image.48. The image processing system of claim 47, wherein the profileselection processor is configured to select the output profile is basedon a color dispersion of existing light conditions detected in thepre-image.
 49. The image processing system of claim 47, wherein theprofile selection processor is configured to select the output profilebased on a level of illumination detected in the pre-image.
 50. Theimage processing system of claim 47, wherein the profile selectionprocessor is configured to select the output profile based on thepre-image to illuminate the target scene at a level required for theimage sensor to capture an image above a threshold quality level.